2021-33193 | Apache HTTP Server mod_proxy access control

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0	$5k-$25k	0.80

A vulnerability was found in Apache HTTP Server up to 2.4.48 (Web Server). It has been classified as critical. This affects an unknown part of the component mod_proxy. The manipulation with an unknown input leads to a privilege escalation vulnerability. CWE is classifying the issue as CWE-284. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.

The weakness was disclosed 08/16/2021 as ecebcc035ccd8d0e2984fe41420d9e944f456b3c. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2021-33193 since 05/19/2021. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/18/2021). MITRE ATT&CK project uses the attack technique T1068 for this issue.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

Type

• Web Server

Vendor

• Apache

Name

• HTTP Server

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VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍
Class: Privilege escalation
CWE: CWE-284
ATT&CK: T1068

Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfoedit

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: github.com

05/19/2021 CVE assigned
08/16/2021 +89 days Advisory disclosed
08/16/2021 +0 days VulDB entry created
08/18/2021 +2 days VulDB last updateVendor: https://www.apache.org/

Advisory: ecebcc035ccd8d0e2984fe41420d9e944f456b3c
Status: Confirmed

CVE: CVE-2021-33193 (🔒)

Created: 08/16/2021 13:51
Updated: 08/18/2021 14:39
Changes: (2) source_cve_assigned source_cve_nvd_summary
Complete: 🔍

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